The deficiency of one of the following in the diet of a person for a considerable time can lead to a disease called night blindness. This one is:

The number of images formed of an object placed between two plane mirrors inclined at right angles to each other is:

As the angle between two plane mirrors is decreased gradually, the number of images of an object placed between them:

Which of the following is not a part of the human eye?

How does the eye change in order to focus on near or distant objects?